You don't need 50 dogs. That's just ridiculous.
Before you even get started or start thinking about doing this, you need to get in touch with people who actually hunt wild boar with dogs.
Some use hounds, like Treeing Walkers and Plotts, others use American Bulldogs and pit mixes.
This is not something you do alone, nor is it something you do with only 1 dog. Wild Boars are dangerous animals, they can rip you and your dog apart with their tusks, they are very quick and they will eat anything, which includes animals and man.
edit: Larry is correct in the fact that the dogs do not kill the boar, they just hold it, basically immobilizing it, until the hunter kills it.